The present invention relates to a new and improved method of dispersing a material containing waste paper, wherein a dewatering machine is connected upstream or ahead of a dispersion apparatus or disperger.
When paper products are manufactured in modern papermaking machines, high requirements are placed upon the constancy or consistency of the quality, for instance, optical and technological constancy or regularity, of the material or stock supplied to the papermaking machine. While the constancy of quality of the material delivered to the papermaking machine is generally governable or controllable when primary raw materials or stock, such as fresh cellulose and mechanical wood pulp are used, quality fluctuations are a serious problem when waste paper is processed.
One of the objectives of the stock preparation process is to compensate as far as possible for the quality fluctuations emanating from the use of waste paper as the raw material. In no event can there be tolerated an increase of the quality fluctuations by virtue of the stock preparation process.
In modern installations for the preparation of waste paper, it is common to homogenize the waste paper stock subsequent to the stock preparation process. The equipment or installations used for this purpose are generally referred to as homogenizing or dispersion installations or machines. A measure of the degree of the dispersing effect or action is the energy density with which the material is processed or treated in the homogenizing or dispersion machine. At the same time, the paper-technological qualities of the finished stock are also determined by this treatment.
It is often necessary for operation reasons to operate the waste paper installation with different throughput quantities. This is associated with the adverse effect that during the dispersion process it is necessary to operate with continuously varying specific work, i.e. dispersion work, related to the actual material or stock throughput. The reason for this adverse effect is the non-linear relationship between the dispersion power or performance and the throughput of material through the dispersion apparatus or disperger. The specific dispersion work, in case of a throughput change of the material which is to dispersed, therefore only can be maintained constant when the dispersion power or performance is re-corrected.